/**
 * =========================================================================
 * File        : byte_order.cpp
 * Project     : 0 A.D.
 * Description : byte order (endianness) support routines.
 *
 * @author Jan.Wassenberg@stud.uni-karlsruhe.de
 * =========================================================================
 */

/*
 * Copyright (c) 2003 Jan Wassenberg
 *
 * Redistribution and/or modification are also permitted under the
 * terms of the GNU General Public License as published by the
 * Free Software Foundation (version 2 or later, at your option).
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "precompiled.h"
#include "byte_order.h"


#ifndef swap16

u16 swap16(const u16 x)
{
	return (u16)(((x & 0xff) << 8) | (x >> 8));
}

u32 swap32(const u32 x)
{
	return (x << 24) |
		(x >> 24) |
		((x << 8) & 0x00ff0000) |
		((x >> 8) & 0x0000ff00);
}

u64 swap64(const u64 x)
{
	const u32 lo = (u32)(x & 0xFFFFFFFF);
	const u32 hi = (u32)(x >> 32);
	u64 ret = swap32(lo);
	ret <<= 32;
	// careful: must shift var of type u64, not u32
	ret |= swap32(hi);
	return ret;
}

#endif	// #ifndef swap16


//-----------------------------------------------------------------------------

u16 to_le16(u16 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return swap16(x);
#else
	return x;
#endif
}

u32 to_le32(u32 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return swap32(x);
#else
	return x;
#endif
}

u64 to_le64(u64 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return swap64(x);
#else
	return x;
#endif
}


u16 to_be16(u16 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return x;
#else
	return swap16(x);
#endif
}

u32 to_be32(u32 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return x;
#else
	return swap32(x);
#endif
}

u64 to_be64(u64 x)
{
#if BYTE_ORDER == BIG_ENDIAN
	return x;
#else
	return swap64(x);
#endif
}


u16 read_le16(const void* p)
{
	return to_le16(*(u16*)p);
}

u32 read_le32(const void* p)
{
	return to_le32(*(u32*)p);
}

u64 read_le64(const void* p)
{
	return to_le64(*(u64*)p);
}


u16 read_be16(const void* p)
{
	return to_be16(*(u16*)p);
}

u32 read_be32(const void* p)
{
	return to_be32(*(u32*)p);
}

u64 read_be64(const void* p)
{
	return to_be64(*(u64*)p);
}


void write_le16(void* p, u16 x)
{
	*(u16*)p = to_le16(x);
}

void write_le32(void* p, u32 x)
{
	*(u32*)p = to_le32(x);
}

void write_le64(void* p, u64 x)
{
	*(u64*)p = to_le64(x);
}


void write_be16(void* p, u16 x)
{
	*(u16*)p = to_be16(x);
}

void write_be32(void* p, u32 x)
{
	*(u32*)p = to_be32(x);
}

void write_be64(void* p, u64 x)
{
	*(u64*)p = to_be64(x);
}